What is the most likely diagnosis for a patient presenting with fever, unilateral conjunctivitis with discharge, and tonsillar exudates, whose relative has fever and bilateral conjunctivitis?

Adenovirus Infection (Pharyngoconjunctival Fever)

The most likely diagnosis is adenovirus infection, specifically pharyngoconjunctival fever (PCF), given the constellation of fever, conjunctivitis, pharyngitis (tonsillar exudates), and household transmission pattern. 1, 2

Clinical Reasoning

The patient's presentation is classic for pharyngoconjunctival fever, one of the two well-defined adenoviral keratoconjunctivitis syndromes:

• Fever, pharyngitis, and bilateral conjunctivitis form the diagnostic triad of PCF, though initial presentation may be unilateral before progressing to bilateral involvement 1, 2
• Tonsillar exudates represent the pharyngeal component of this syndrome 1
• Household transmission is highly characteristic, as adenovirus is extremely contagious through direct contact, respiratory droplets, and fomites 2, 3
• The relative's bilateral conjunctivitis with fever further supports a viral etiology spreading within the household 1

Why Not the Other Options

Streptococcal pharyngitis would not explain:

• The conjunctivitis in either patient (strep does not cause conjunctivitis) 1
• The household member's isolated bilateral conjunctivitis without pharyngeal symptoms
• The discharge from the conjunctiva, which is not a feature of streptococcal infection

Kawasaki disease is excluded because:

• It requires specific diagnostic criteria including prolonged fever (≥5 days), not just 2 days
• Conjunctivitis in Kawasaki is typically bilateral, nonexudative, and without discharge 1
• The household transmission pattern does not fit Kawasaki disease, which is not contagious
• Tonsillar exudates are not a feature of Kawasaki disease

Key Diagnostic Features of Adenoviral PCF

Clinical presentation includes: 1, 2

• Abrupt onset of high fever
• Pharyngitis with tonsillar involvement
• Bilateral conjunctivitis (though may start unilaterally)
• Periauricular or preauricular lymph node enlargement
• Watery to serofibrinous discharge

Epidemiological clues: 2, 3

• More frequent during warmer months
• Highly contagious with household clustering
• Transmission through hand-to-eye contact, respiratory droplets, and contaminated surfaces

Management Approach

Treatment is primarily supportive: 4, 2, 5

• Artificial tears and cool compresses for symptom relief
• Warm soaks may relieve itching and burning
• Most cases are self-limited, resolving within 5-14 days 1

Infection control is critical: 5

• Avoid touching eyes
• Frequent handwashing
• Use disposable towels
• Avoid group activities while discharge is present
• The virus is extremely resistant to physical and chemical agents 3

Topical antibiotics are NOT indicated unless bacterial coinfection is suspected or in high-risk patients such as children 4, 5

Important Caveats

Avoid topical corticosteroids in the acute phase, as they can mask serious conditions and may worsen viral replication 5

Monitor for corneal involvement with fluorescein staining, as adenovirus can progress to epidemic keratoconjunctivitis with subepithelial infiltrates and potential long-term visual sequelae 1, 6

Rapid diagnostic tests are now available and can decrease unnecessary antibiotic use, though diagnosis remains primarily clinical 2